* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    background-image: url(../img/backgound.jpg);
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}

.nav {
    width: 100%;
    height: 50px;
    background-color: rgba(51, 51, 51, 0.6);
    color: white;
    display: flex;
    align-items: center;
}

.nav img {
    width: 40px;
    height: 40px;
    border-radius: 50%;

    margin-left: 30px;
    margin-right: 10px;
}

.nav .spacer {
    width: 70%;
}

.nav a {
    color: white;
    padding: 0 10px;
    text-decoration: none;
}

/* 接下来是版心相关的样式 */
.container {
    width: 1000px;
    /* -留出空格防止浏览器无法识别 */
    height: calc(100% - 50px);
    margin: auto;
    display: flex;
    justify-content: space-between;
}

.container .left {
    height: 100%;
    width: 200px;
}

.container .right {
    height: 100%;
    width: 795px;
    
    background-color: rgba(255, 255, 255, 0.8);
    border-radius: 10px;
    overflow: auto;
}

.card {
    background-color: rgba(255, 255, 255, 0.8);
    border-radius: 10px;

    padding: 30px;
}

.card img {
    width: 140px;
    height: 140px;
    border-radius: 50%;
}

.card h3 {
    text-align: center;
    padding: 10px;
}

.card a {
    /* a 默认是行内元素. 行内元素的很多边距不生效. 为了简单起见, 直接设为块级元素. */
    display: block;
    text-align: center;
    text-decoration: none;
    color: #999;
    padding: 10px;
}

.card .counter {
    display: flex;
    justify-content: space-around;
    padding: 5px;
}